Devices and methods facilitating sleeve gastrectomy procedures

ABSTRACT

A device for use in bariatric surgery includes a tube member, a coupling member, and a rod member. The tube member includes a proximal portion and a distal portion having a distal end. The coupling member is affixed to the tube member. The rod member includes a proximal portion and a distal portion having a distal end. The rod member is slidably coupled with the coupling member. The distal end of the rod member is fixedly coupled to the distal end of the tube member. The proximal portion of the rod member is translatable relative to the tube member to transition the distal portion of the rod member between a contracted position, wherein the distal portion of the rod member extends along the distal portion of the tube member, and a deployed position, wherein the distal portion of the rod member bows outwardly relative to the tube member.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of and priority to U.S. ProvisionalPatent Application No. 61/716,109, filed on Oct. 19, 2012, the entirecontents of which are incorporated herein by reference.

BACKGROUND

1. Technical Field

The present disclosure relates generally to bariatric surgery and, moreparticularly, to devices and methods that facilitate performing sleevegastrectomy procedures.

2. Background of Related Art

Obesity is reaching epidemic proportions in many regions of the world,particularly in the United States. In order to treat obesity, varioussurgical procedures have been developed including, for example, gastricbypass, adjustable gastric banding, and sleeve gastrectomy. The goal ineach of these procedures is to reduce the patient's stomach capacity torestrict the amount of food that the patient can eat. The reducedstomach capacity, in turn, results in a feeling of fullness for thepatient after ingesting a relatively smaller amount of food. Thus, thepatient can achieve significant weight loss.

Sleeve gastrectomy involves transecting the stomach, e.g., using astapling device or other suitable device, to reduce the patient'sstomach volume. Sleeve gastectomy procedures are often aided by the useof a bougie, which serves as a guide or template for transecting thestomach to the appropriate configuration while inhibiting inadvertenttransection of stomach or esophageal tissue. Once the stomach has beenappropriately transected, the bougie is removed and a leak test isperformed to determine whether there are any areas of extravasation.

There is a need for a device and/or method of positioning the stomach,or other hollow organ, to avoid shifting of the sides of the organ withrespect to one another during transection, stapling etc., in a surgicalprocedure. There is a need for a simpler, more convenient way to performa leak test, visualize the transected tissue, etc.

SUMMARY

In an aspect of the present disclosure, a medical device comprises aflexible tube that is hollow and contains a channel extending from aproximal opening to a distal closed tapered end, a series ofperforations or openings towards the distal end of the tube allowing forsuction fixation of tissue a flexible component alongside the tube thatwhen deployed allows for the stretching of a stomach to its originalshape, the application of suction placing the tube along a lessercurvature of the stomach, fixing anterior and posterior walls of thestomach, and preventing their movement while the surgeon transects thestomach, the suction allowing for clear identification of the tube.

The flexible component is desirably an attached movable element. Thetube can be made of silicone. A coupling device that holds the movableelement to the tube can be provided. The movable element can bedeployable to align the stomach by evening out the anterior andposterior walls of the stomach and by pushing the tube and a perforatedarea of the tube towards the lesser curvature of the stomach. Suctioncan be applied at a proximal end of the tube. Air or colored fluid canbe instilled into a proximal end of the tube.

In a further aspect, a device for use in bariatric surgery provided inaccordance with the present disclosure generally includes an elongatedflexible tube member, a coupling member, and an elongated resilient rodmember. The tube member defines a proximal portion and a distal portionhaving a distal end. The coupling member is affixed to the tube memberintermediate the proximal and distal portions of the tube member. Therod member defines a proximal portion and a distal portion having adistal end. The rod member is slidably coupled to the coupling memberintermediate the proximal and distal portions of the rod member. Thedistal end of the rod member is fixedly coupled to the distal end of thetube member. The proximal portion of the rod member is translatablerelative to the tube member to transition the distal portion of the rodmember between a contracted position, wherein the distal portion of therod member extends along the distal portion of the tube member, and adeployed position, wherein the distal portion of the rod member bowsoutwardly relative to the tube member.

In embodiments, the tube member defines a lumen extending therethroughand the distal portion of the tube member defines a plurality ofapertures in fluid communication with the lumen.

In embodiments, a suction source is provided. The suction source isoperably coupled to the tube member and configured to apply suction tothe lumen of the tube member.

In embodiments, a fluid source is provided. The fluid source is operablycoupled to the tube member and configured to supply fluid to the lumenof the tube member.

In embodiments, an end cap is affixed to the distal end of the tubemember. The distal end of the rod member is affixed to the end cap.Further, the distal end of the rod member may be monolithically formedwith the end cap. The cap can house a releasable connection of the rodmember and tube member, or other mechanisms.

In embodiments, in the deployed position, the distal portion of the rodmember defines a curvature complementary to a greater curvature portionof a patient's stomach.

In embodiments, the coupling member includes a ring disposed about thetube member. The ring slidably receives the rod member.

Also provided in accordance with the present disclosure is a system foruse in bariatric surgery. The system includes a device having anelongated flexible tube member, a coupling member, and an elongatedresilient rod member. The tube member includes a lumen extendingtherethrough and defines a proximal portion and a distal portion havinga distal end. The distal portion of the tube member defines a pluralityof apertures therethrough in fluid communication with the lumen. Thecoupling member is affixed to the tube member intermediate the proximaland distal portions of the tube member. The rod member defines aproximal portion and a distal portion having a distal end. The rodmember is slidably coupled with the coupling member intermediate theproximal and distal portions of the rod member. The distal end of therod member is fixedly coupled to the distal end of the tube member. Theproximal portion of the rod member is translatable relative to the tubemember to transition the distal portion of the rod member between acontracted position, wherein the distal portion of the rod memberextends along the distal portion of the tube member, and a deployedposition, wherein the distal portion of the rod member bows outwardlyrelative to the tube member. The system further includes a suctionsource and a fluid source. The suction source is operably coupled to thetube member and configured to apply suction to the lumen for suctioningstomach contents through the apertures and into the lumen and/or forsuctioning stomach tissue to the distal portion of the tube member. Thefluid source is operably coupled to the tube member and configured tosupply fluid to the tube member for delivery to a patient's stomach viathe plurality of apertures.

In embodiments, the device further includes an end cap affixed to thedistal end of the tube member. The distal end of the rod member isaffixed to the end cap. The system end cap may further be configured toseal the lumen at the distal end of the tube member. The distal end ofthe rod member may be monolithically formed with the end cap.

In embodiments, in the deployed position, the distal portion of the rodmember defines a curvature complementary to a greater curvature portionof a patient's stomach.

In embodiments, one or more control members is provided for controllinga suction pressure applied by the suction source and/or controlling aflow rate of fluid provided from the fluid source.

A method of bariatric surgery provided in accordance with the presentdisclosure includes inserting a device, e.g., a device similar to any ofthe embodiments detailed above, at least partially into a patient'sstomach and transitioning the device from a contracted condition to adeployed condition. In the deployed condition, the distal portion of therod member bows outwardly relative to the tube member to complementarilymate with a greater curvature portion of the patient's stomach. Themethod further includes applying suction to retain a lesser curvatureportion of the patient's stomach in complementary mating relation withthe distal portion of the tube member, transitioning the device from thedeployed condition back to the contracted condition, and transecting thepatient's stomach adjacent the tube member.

In embodiments, the proximal portion of the rod member is translateddistally relative to the tube member to transition the device from thecontracted condition to the deployed condition. In embodiments, theproximal portion of the rod member is translated proximally relative tothe tube member to transition the device from the deployed conditionback to the contracted condition.

In embodiments, the method further includes introducing fluid throughthe tube member and into the patient's stomach to perform a leak test.

In embodiments, transecting the patient's stomach includes transectingthe patient's stomach to form a tubular structure disposed about thedistal portion of the tube member and having a diameter similar to adiameter of the distal portion of the tube member.

BRIEF DESCRIPTION OF THE DRAWINGS

Various aspects and features of the present disclosure are describedherein with reference to the drawings wherein:

FIG. 1 is a schematic illustration showing a device provided inaccordance with the present disclosure inserted into a patient'sstomach;

FIG. 2 is a perspective view of a system provided in accordance with thepresent disclosure including the device of FIG. 1 disposed in a firstcondition;

FIG. 3 is a perspective view of the device of FIG. 1, disposed in asecond condition; and

FIG. 4 is a flow diagram illustrating a method of performing a bariatricsurgical procedure provided in accordance with the present disclosure.

DETAILED DESCRIPTION OF EMBODIMENTS

Embodiments of the present disclosure are detailed below with referenceto the drawings in which like reference numerals designate identical orcorresponding elements in each of the several views. Throughout thisdescription, the term “proximal” will refer to the portion of the deviceor component thereof that is closest to the user and the term “distal”will refer to the portion of the device or component thereof that isfarthest from the user.

Turning now to FIGS. 1-3, a device provided in accordance with thepresent disclosure and configured for use during a sleeve gastrectomyprocedure is shown generally identified by reference numeral 10. As bestshown in FIGS. 2-3, device 10 includes an elongated tube member 20 andan elongated rod member 40 coupled to tube member 20. The materials forthe tube member 20 and the rod member are generally polymeric materialsappropriate for surgical applications, such as the materials used tomake a bougie or catheter. The tube member is hollow, whereas the rodmember can be hollow or solid. Tube member 20 is formed from flexiblematerials such as silicone and rubber, although other suitable flexiblematerials are also contemplated. Tube member 20 has a distal portion 22and a proximal portion 24 and defines a lumen 26 extending therethrough.A plurality of perforations or apertures 28 are defined through an outerwall of distal portion 22 of tube member 20. Apertures 28 enable fluidcommunication through the outer wall of tube member 20 between lumen 26and the exterior of tube member 20. Tube member 20 further includes adistal end cap 30. The distal end of the tubular member 20 is closed inany appropriate manner. Distal end cap 30 may define a rounded taperedconfiguration, blunt conical configuration, or any other suitableconfiguration that facilitates atraumatic insertion into a patient'sstomach “ST” (FIG. 1). Distal end cap 30 is affixed to the distal end oftube member 20 in sealing engagement therewith to seal off lumen 26 atthe distal end of tube member 20.

Tube member 20 is configured to connect to a suction source “S” and afluid source “F.” Suction source “S” is operable to provide suctionwithin lumen 26 for suctioning fluids, stomach contents, etc. throughapertures 28 and into lumen 26 for removal and/or for suctioning stomachtissue into contact with tube member 20. One or more control members 32,e.g., a valve, may interdisposed between tube member 20 and the suctionsource “S” to control the suction force being applied, although controlsmay alternatively or additionally provided on a user interface (notshown) of the suction source “S.” Fluid source “F” is configured to pumpfluid, e.g., water or air, into lumen 26 of tube member 20 and outthrough apertures 28 into the stomach “ST” (FIG. 1). Similar to suctionsource “S,” the fluid source “F” may include one or more control members34, e.g., a valve, interdisposed between tube member 20 and the fluidsource “F” to control the flow rate and/or pressure of fluid beingpumped through lumen 26 of tube member 20, although controls mayalternatively or additionally provided on a user interface (not shown)of the fluid source “F.” The tube member 20 can have one or morepassageways.

Continuing with reference to FIGS. 2-3, rod member 40 is formed from asemi-rigid, resiliently flexible material, e.g., a suitable elastomer,and defines a length greater than the length of tube member 20 such thatrod member 40 can be accessed outside the patient and/or remotely of thesurgical site. Rod member 40 defines a distal portion 42 having a distalend 43 and a proximal portion 44. Distal end 43 of rod member 40 isintegrally, i.e., monolithically, formed with or otherwise affixed todistal end cap 30. A coupling 50, e.g., a ring, sleeve, hook, latch,etc., affixed to tube member 20 slidably receives a portion of rodmember 40 therethrough to slidably couple rod member 40 to tube member20 intermediate the distal and proximal portions 22, 24, respectively,of tube member 20. As a result of the above-configuration, rod member 40is slidable through coupling 50 and relative to tube member 20 between acontracted position corresponding to a first condition of device 10(FIG. 2), wherein distal portion 42 of rod member 40 extends along andabuts the outer surface of tube member 20 is substantially parallelrelation relative thereto, and a deployed position corresponding to asecond condition of device 10 (FIG. 3), wherein distal portion 42 of rodmember 40 is bowed outwardly from tube member 20 and is spacedtherefrom. In the deployed position, rod member 40 defines aconfiguration that generally complements the curvature of the greatercurvature portion “C2” of the stomach “ST” (FIG. 1). Preferably, theflexibility and resilience and dimensioning of the member 40 is suchthat member 40 automatically forms a half-heart shape, with a large,bowed, curvature adjacent the proximal portion 44. Such a shapecomplements the greater curvature of the stomach. These features can beadapted to applications in other hollow organs as well. The rod membershould be strong enough to stretch out the stomach, and reposition theanterior and posterior walls of the stomach. Proximal portion 44 of rodmember 40 may be grasped and manipulated relative to tube member 20 totransition rod member 40 between the contracted and deployed positions.As mentioned above, rod member 40 is dimensioned such that proximalportion 44 is accessible from outside the patient, thus readily enablingmanipulation thereof. More specifically, translating rod member 40distally relative to tube member 20 and coupling 50 urges rod member 40distally through coupling 50 such that distal portion 42 of rod member40 is bowed outwardly relative to tube member 20 towards the deployedposition. Translating rod member 40 proximally relative to tube member20 pulls rod member 40 proximally through coupling 50 such the distalportion 42 of rod member 40 is pulled inwardly relative to tube member20 towards the contracted position. As an alternative to manuallymanipulating rod member 40, an actuator or actuation assembly (notshown) may be coupled to the proximal ends of tube member 20 and rodmember 40 to enable selective translation of rod member 40 relative totube member 20.

Referring to FIG. 4, in conjunction with FIGS. 1-3, the use of device 10during the course of a sleeve gastrectomy procedure is described.However, it is also envisioned that device 10 be capable of use in othersimilar surgical procedures, within hollow organs other than thestomach, etc. Initially, with rod member 40 disposed in the contractedcondition, device 10, lead by distal end cap 30, is inserted through thepatient's mouth, esophagus, and into the patient's stomach “ST” to theposition shown in FIG. 1, wherein at least distal portion 22 of tubemember 20, coupling 50, and distal portion 42 of rod member 40 aredisposed within the patient's stomach “ST” (step S410). Once thisposition has been achieved, proximal portion 44 of rod member 40 istranslated distally relative to tube member 20 such that distal portion42 of rod member bows outwardly relative to tube member 20 towards thedeployed position. As distal portion 42 of rod member 40 bows outwardlytowards the deployed position, tube member 20 is urged towards and intocomplementary mating relation with the lesser curvature portion “C1” ofthe stomach “ST,” while distal portion 42 of rod member 40 is urgedtowards and into complementary mating relation with the greatercurvature portion “C2” of the stomach “ST” (step S420), engaging andflattening the stomach. As such, the orientation of device 10 with tubemember 20 extending along the lesser curvature portion “C1” of thestomach “ST” between the esophageal sphincter “E” and the pyloricsphincter “P” can be readily achieved. As a result of this configurationof device 10 in the second condition, the above-described orientation ofdevice 10 within the stomach is maintained despite spasms, folding,spiraling, and/or shifting of the stomach “ST.” Further, theconfiguration of device 10 allows for proper positioning within thestomach “ST” without the assistance of an viewing instrument, e.g., anendoscope (not shown).

Once the proper orientation of tube member 20 of device 10 has beenachieved, suction source “S” may be activated to apply suction withinlumen 26 for suctioning any remaining contents within the stomach “ST”into lumen 26 of tube member 20 through apertures 28. Application ofsuction within lumen 26 also suctions the lesser curvature portion “C1”of the stomach “ST” to the outer periphery of tube member 20, to ensureand maintain the complementary mating relation of tube member 20 withthe lesser curvature portion “C1” of the stomach “ST” (step S430).Control member 32 may be manipulated or otherwise controlled to applysufficient suction to maintain the relative position of tube member 20without damaging surrounding tissue.

With tube member 20 maintained in position relative to the lessercurvature portion “C1” of the stomach “ST” as a result of the appliedsuction, proximal portion 44 of rod member 40 is translated proximallyrelative to tube member 20 such the distal portion 42 of rod member 40is pulled inwardly relative to tube member 20 back to the contractedposition (step S440). As suction is maintained at this point, tubemember 20 is maintained in the positioned detailed above despitecontraction of distal portion 42 of rod member 40.

Once distal portion 42 of rod member 40 has been returned to thecontracted position, transection of the stomach “ST” adjacent tubemember 20 on a opposite side of tube member 20 relative to the lessercurvature portion “C1” of the stomach “ST” may be effected in anysuitable fashion (step S450), e.g., using a stapling device or othersuitable device. Transection in this manner reforms the stomach “ST” toa tubular-shaped configuration that slightly larger than the outerdimension of tube member 20 and extends between the esophageal sphincter“E” and the pyloric sphincter “P.” The suction is maintained while thestomach tissue is transected and stapled, the shape of the tube member20 forming a visible bulge. As can be appreciated, the diameter of tubemember 20 may be selected in accordance with a desired diameter of thetubular-shape reformed stomach. The remaining stomach tissue is removedfrom the patient.

Upon completion of the stomach transection, the applied suction isremoved and a leak test is performed (step S460). The leak test isperformed by activating the fluid source “F” to pump fluid through lumen26 of tube member 20 and into the stomach via apertures 28. The fluidmay be air, colored water, or other suitable gaseous or liquid leak testagent. The fluid is pumped into the stomach “ST,” e.g., via controllingcontrol member 34, to achieve a pressure within the stomach “ST”sufficient to test the transected stomach tissue for extravasation. Ifextravasation is detected, the leak is repaired prior to completing theprocedure, by suturing or any other appropriate method. The leak test isrepeated after repairing the portion or portions of transected tissuewhere extravasation is detected, until no further extravasation isdetected. Ultimately, device 10 is withdrawn from the patient's stomach“ST.” A scope can be provided with the device, and the tube member mayhave a separate passageway for the scope or other devices.Alternatively, the user of the device may pass a scope through thesingular passageway as needed.

In any of the embodiments disclosed herein, the tube member can be madeof a clear polymer and a scope or camera is provided. In any of theembodiments disclosed herein, an ultrasound probe can be provided.

In any of the embodiments disclosed herein, the rod member 40 can bedetachable from the tube member 20. The attachment or connection at thedistal end of the tube member 20 can be frangible, releasable, etc., toallow the rod member 40 to be detached from the tube member 20. In thisway, the user of the device has removed the rod member 40 from the site,while maintaining the position of the stomach (using suction, asdiscussed, avoiding transecting or stapling the rod member 40.

It will be understood that various modifications may be made to theembodiments of the present disclosure herein. Therefore, the abovedescription should not be construed as limiting, but merely asexemplifications of embodiments. Those skilled in the art will envisionother modifications within the scope and spirit of the presentdisclosure.

What is claimed is:
 1. A medical device, comprising: a flexible tubethat is hollow and contains a channel extending from a proximal openingto a distal closed tapered end; a series of perforations or openingstowards the distal end of the tube allowing for suction fixation oftissue; a flexible component alongside the tube that when deployedallows for the stretching of a stomach to its original shape; theapplication of suction placing the tube along a lesser curvature of thestomach, fixing anterior and posterior walls of the stomach, andpreventing their movement while the surgeon transects the stomach, thesuction allowing for clear identification of the tube.
 2. The medicaldevice of claim 1, wherein the flexible component is an attached movableelement.
 3. The medical device of claim 1, wherein the tube is made ofsilicone.
 4. The medical device of claim 2, further comprising acoupling device that holds the movable element to the tube.
 5. Themedical device of claim 2, the movable element being deployable to alignthe stomach by evening out the anterior and posterior walls of thestomach and by pushing the tube and a perforated area of the tubetowards the lesser curvature of the stomach.
 6. The medical device ofclaim 2, wherein suction is applied at a proximal end of the tube. 7.The medical device of claim 2, wherein air or colored fluid is instilledinto a proximal end of the tube.
 8. A device for use in bariatricsurgery, comprising: an elongated flexible tube member defining aproximal portion and a distal portion having a distal end; a couplingmember affixed to the tube member intermediate the proximal and distalportions of the tube member; and an elongated resilient rod memberdefining a proximal portion and a distal portion having a distal end,the rod member slidably coupled with the coupling member intermediatethe proximal and distal portions of the rod member, the distal end ofthe rod member fixedly coupled to the distal end of the tube member, theproximal portion of the rod member translatable relative to the tubemember to transition the distal portion of the rod member between acontracted position, wherein the distal portion of the rod memberextends along the distal portion of the tube member, and a deployedposition, wherein the distal portion of the rod member bows outwardlyrelative to the tube member.
 9. The device according to claim 8, whereinthe tube member defines a lumen extending therethrough and wherein thedistal portion of the tube member defines a plurality of apertures influid communication with the lumen.
 10. The device according to claim 8,further including a suction source operably coupled to the tube memberand configured to apply suction to the lumen of the tube member.
 11. Thedevice according to claim 8, further including a fluid source operablycoupled to the tube member and configured to supply fluid to the lumenof the tube member.
 12. The device according to claim 8, furtherincluding an end cap affixed to the distal end of the tube member, thedistal end of the rod member affixed to the end cap.
 13. The deviceaccording to claim 12, wherein the distal end of the rod member ismonolithically formed with the end cap.
 14. The device according toclaim 8, wherein, in the deployed position, the distal portion of therod member defines a curvature complementary to a greater curvatureportion of a patient's stomach.
 15. The device according to claim 8,wherein the coupling member includes a ring disposed about the tubemember and slidably receiving the rod member.
 16. A system for use inbariatric surgery, comprising: a device, including: an elongatedflexible tube member having a lumen extending therethrough and defininga proximal portion and a distal portion having a distal end, the distalportion of the tube member defining a plurality of aperturestherethrough in fluid communication with the lumen; a coupling memberaffixed to the tube member intermediate the proximal and distal portionsof the tube member; and an elongated resilient rod member defining aproximal portion and a distal portion having a distal end, the rodmember slidably coupled to the coupling member intermediate the proximaland distal portions of the rod member, the distal end of the rod memberfixedly coupled to the distal end of the tube member, the proximalportion of the rod member translatable relative to the tube member totransition the distal portion of the rod member between a contractedposition, wherein the distal portion of the rod member extends along thedistal portion of the tube member, and a deployed position, wherein thedistal portion of the rod member bows outwardly relative to the tubemember; a suction source operably coupled to the tube member andconfigured to apply suction to the lumen for suctioning stomach contentsthrough the apertures and into the lumen and for suctioning stomachtissue to the distal portion of the tube member; and a fluid sourceoperably coupled to the tube member and configured to supply fluid tothe tube member for delivery to a patient's stomach via the plurality ofapertures.
 17. The system according to claim 16, further including anend cap affixed to the distal end of the tube member, the distal end ofthe rod member affixed to the end cap.
 18. The system according to claim17, wherein the end cap seals the lumen at the distal end of the tubemember.
 19. The system according to claim 17, wherein the distal end ofthe rod member is monolithically formed with the end cap.
 20. The systemaccording to claim 16, wherein, in the deployed position, the distalportion of the rod member defines a curvature complementary to a greatercurvature portion of a patient's stomach.
 21. The system according toclaim 16, further including a first control member configured to controla suction pressure applied by the suction source.
 22. The systemaccording to claim 16, further including a second control memberconfigured to control a flow rate of fluid provided from the fluidsource.
 23. A method of bariatric surgery, comprising: inserting adevice at least partially into a patient's stomach, the deviceincluding: an elongated flexible tube member defining a proximal portionand a distal portion having a distal end; and an elongated resilient rodmember defining a proximal portion and a distal portion having a distalend, the rod member slidably coupled to the tube member intermediate theproximal and distal portions of the tube member, the distal end of therod member fixedly coupled to the distal end of the tube member;transitioning the device from a contracted condition to a deployedcondition wherein, in the deployed condition, the distal portion of therod member bows outwardly relative to the tube member to complementarilymate with a greater curvature portion of the patient's stomach; applyingsuction to retain a lesser curvature portion of the patient's stomach incomplementary mating relation with the distal portion of the tubemember; transitioning the device from the deployed condition back to thecontracted condition; and transecting the patient's stomach adjacent thetube member.
 24. The method according to claim 23, wherein the proximalportion of the rod member is translated distally relative to the tubemember to transition the device from the contracted condition to thedeployed condition.
 25. The method according to claim 23, wherein theproximal portion of the rod member is translated proximally relative tothe tube member to transition the device from the deployed conditionback to the contracted condition.
 26. The method according to claim 23,further including introducing fluid through the tube member and into thepatient's stomach to perform a leak test.
 27. The method according toclaim 23, wherein transecting the patient's stomach includes transectingthe patient's stomach to form a tubular structure disposed about thedistal portion of the tube member and having a diameter similar to adiameter of the distal portion of the tube member.